instmctions): The Histopathology Core (Core B) is an established Core facility of the Program Project that has the overall goal to enhance and facilitate the research of the individual Research Units by providing the following histological services to Program members: 1. Fixation, processing, embedding, and storage of tissues a. Assistance with tissue collection and fixation b. Processing and embedding in paraffin c. Freezing of tissues d. Storage of fixed and processed specimens 2. Tissue secfioning a. Preparafion of paraffin sections b. Preparafion of frozen and live tissue sections 3. Standard and immunohistological staining procedures a. Standard and specialized histochemical staining b. Immunohistological staining with enzyme- or fluorochrome-labeled antibodies c. Antigen retrieval and signal ampliflcafion methods d. TUNEL and BrdU assays for detecfion of apoptotic and proliferating cells 4. Assistance with design, microscopic analysis, and data interpretation of histological studies a. Advice on experimental design of histological studies b. Assistance with microscopic analysis, histological evaluation, and photodocumentafion c. Training in fissue collecfion, staining methods, and histological interpretafion The Core is fully equipped and has highly experienced personnel to provide these services at the highest technical quality in a cost-effective manner. RELEVANCE (See instructions): Proper evaluafion of the complex cellular and molecular events that occur in the intestinal tract and beyond under resting and challenge conditions requires extensive histological analysis. The successful conduct of histological studies depends on an equipment infrastructure and expertise that are unique to the field, and are best provided through a dedicated Core service arrangement.